Conventionally, an electrical junction box is known in which an insulating substrate and a bus bar board are stacked and fixed to a heat-dissipating member. In Publication JP-A-2003-164039 (P2003-164039A), there are provided (i) a circuit structural body in which a bus bar structural plate constituted by a plurality of bus bars stacked with a printed circuit board and (ii) a case that includes this circuit structural body. Electronic components such as relays or the like are mounted on the printed circuit board, and a heat radiation plate is arranged at a bottom portion of the case. The bus bar structural plate is constituted by many bus bars that correspond to the shape of electroconductive paths. The bus bar structural plate is stacked with a thin printed circuit board, so the strength of the printed circuit board is reinforced.